Brain mri result: there is no signal void from the anterior and posterior circulation what's the medical definition of it and is it bad or not?

Signal Void Brain: On mri, in certain sequences there should be a lack of signal (ie. A black appearance) within the blood vessels. This normal appearance suggests that blood is flowing normally within these blood vessels. If there is a lack of signal void, this could suggest either abnormal blood flow or a complete lack of blood flow. This is abnormal and is concerning. Oftentimes this is associated with a stroke.